Mobile communication devices may include a variety of components including circuit boards, integrated circuit (IC) devices and/or System-on-Chip (SoC) devices. The components may include processing devices, user interface components, storage and other peripheral components that communicate through a shared data communication bus, which may include a serial bus or a parallel bus. In some instances, a shared data communication bus may be implemented using a standardized general-purpose serial interface such as the Inter-Integrated Circuit (I2C or I2C) serial bus and the I3C interface defined by the Mobile Industry Processor Interface (MIPI) Alliance.
General purpose input/output (GPIO) provided in an integrated circuit (IC) device enable an IC designer to define and configure pins that may be customized for particular applications. For example, a GPIO pin may be programmable to operate as an output or as an input pin depending upon a user's needs. A GPIO module or peripheral may control groups of pins which can vary based on the interface requirement. GPIO pins are commonly included in microprocessor and microcontroller applications because they offer flexibility and programmability. For example, an application processor in mobile devices may use a number of GPIO pins to conduct handshake signaling such as inter-processor communication (IPC) with a modem processor.
In many instances, a number of command and control signals are employed to connect different component devices in mobile communication devices. These connections consume precious general-purpose input/output (GPIO) pins within the mobile communication devices and it would be desirable to replace the physical interconnects with signals carried in information transmitted over existing serial data links. However, the serial data links are associated with latencies that can prevent conversion of physical command and control signals to virtual signals, particularly in real-time embedded system applications supported by mobile communication devices that define firm transmission deadlines.
As mobile communication devices continue to include a greater level of functionality, improved serial communication techniques are needed to support low-latency transmissions between peripherals and application processors.